Reinforcement additives

ABSTRACT

The invention concerns reinforcement additives consisting of oligomeric and/or polymeric sulfur-containing organoorganooxysilanes, perhaps other unsaturated hydrocarbon-containing organoorganooxysilanes and reinforcing semiactive, active, and/or highly active carbon blacks, common in rubber, their production, and the use of the additives in perhaps silicatically filled vulcanizable rubber mixtures and compositions and in plastic mixtures or in carbon black dispersions.

TECHNICAL FIELD

The invention concerns reinforcement additives consisting of oligomericor polymeric sulfur-containing organoorganooxysilanes, perhaps otherunsaturated hydrocarbon-containing organoorganooxysilanes, reinforcing,semiactive, active, and/or highly active carbon blacks, which are commonin rubber, and perhaps other known additives, and the preparation anduse of the additives in accordance with the invention in vulcanizable,perhaps silicatically [sic] filled rubber mixtures and compositions, andin plastic mixtures, or in carbon black dispersions.

STATE OF THE ART

The use of sulfur-containing organosilanes in silica-filled rubbers toestablish a chemical bond between rubber helices and a silica surfacehas been known for a long time.

Thus, a number of compounds in pure form have been proposed for theseuses—for example, 3-mercaptopropyltrimethoxysilane (U.S. Pat. No.5,126,510; West German Patent No. 2,524,863);,3-(triethoxysilyl)propylthiocyanate (West German Patent Nos. 2,035,778and 4,100,217); bis[3-(triethoxysilyl)propyl]tetrasulfide (West GermanPatent Nos. 2,255,577, 2,447,614, and, 3,305,373; Japanese Patent No. 610 04 742), or oligo[(triethoxysilyl)organo]bisoligosulfides (EastGerman Patent No. 299,187; European Patent No. 466,066).

The disadvantage in using these pure silanes is either the insufficientprocessing reliability due to increased mixing viscosities and thegreatly reduced starting and completing vulcanization times or aninsufficient reinforcer effect due to excessively low crosslinkingdensities. Another disadvantage is the difficult metering of the liquidadditives and their susceptibility to hydrolysis, which has a negativeeffect, especially in processing in the rubber industry.

Experiments to use the aforementioned monomeric silanes as mixtures orpreparations with silicatic fillers in the rubber, tire, and plasticindustries, described, for example, in West German Patent Nos.2,528,134, 3,314,742, and 3,437,473, fail due to the susceptibility tohydrolysis, instability, or excessively low effectiveness of thesemixtures.

A storage-stable silane-silica preparation based onbis[3-(triethoxysilyl) propyl]tetrasulfide is described in EuropeanPatent No. 442,143. For the preparation of this mixture, containing only5 to 15 parts by weight silane, however, long mixing times (>2) and hightemperatures (>100° C.) are required.

Furthermore, mixtures of bis[3-(triethoxysilyl)propyl]tetrasulfides andcarbon blacks and their use in rubbers have been described in the past.Simple mixtures in the weight ratio of 50 to 50, cited, for example, inWest German Patent No. 2,747,277 and U.S. Pat. No. 5,227,425, exhibitrather good reinforcing effects in silica-filled rubber mixtures, but atthe same time lead to an impairment of the tear propagation resistanceof the vulcanized materials and to a strong decline of the elongation atbreak due to a more rapid strengthening of the rubber. Furthermore, thesilane fraction can be dissolved away completely from the carbon blackby extraction, for example, with diethyl ether, which has a negativeeffect on the stability and effectiveness of the silane-carbon blackmixtures.

Silane-carbon black preparations whose silane fraction cannot bedissolved away by extraction are presented in West German Patent Nos.4,043,537 and 4,119,959. They are suitable only for purely carbonblackfilled rubber mixtures, however, because of their lowsilane-content (0.4 to 5.5 parts by weight) and are prepared accordingto an expensive method (temperature>120° C.). Even more expensivemethods for the fixing of the monomeric silanebis[3-(triethoxysilyl)propyl]tetrasulfide on carbon blacks by upstreamoxidation processes on the carbon black (plasma method, oxidation agentssuch as H₂O₂, nitric acid, ozone) are described in Japanese Patent No.88 31796 and West German Patent No. 3,813,678. Here too, only oneextractable silane fraction of 1 to 5 parts by weight is attained.

All these attempts to improve the rubber-technological characteristicsbegin with a variation of the carbon black or the treatment of itssurface.

DESCRIPTION OF THE INVENTION

The goal of the invention was to prepare new, flowable, odorless, anddust-free reinforcement additives based on oligomeric and/or polymeric,sulfur-containing organoorganooxysilanes and reinforcing, semiactive,active, and/or highly active carbon blacks, common in the rubber, tire,and plastic industries, and a simple method for their preparation.

Another goal of the invention was the implementing of the use ofadditives in accordance with the invention in vulcanizable, perhapssilicatically filled rubber mixtures and compositions and in plasticmixtures or in carbon black dispersions.

Surprisingly, it was discovered that the aforementioned disadvantagescan be overcome if the reinforcement additives consist of oligomericand/or polymeric sulfur-containing organoorganooxysilanes, perhaps otherunsaturated hydrocarbon-containing organoorganooxysilanes, reinforcingsemiactive, active, and/or highly active carbon blacks common in rubber,and perhaps other known additives.

The object of the invention concerns reinforcement additives, consistingof

a) 5 to 70, preferably 40 to 60, parts by weight of one or moreoligomeric and/or polymeric sulfur-containing organoorganooxysilanes ofthe following general formula:

wherein R¹ represents saturated and/or unsaturated, branched, and/orunbranched, substituted and /or unsubstituted, at least trivalenthydrocarbons with 2 to 20 carbon atoms, provided that at least twocarbon-sulfur bonds are contained; R² and R³ denote, independent of oneanother, saturated and/or unsaturated, branched and/or unbranched,substituted and/or unsubstituted hydrocarbons with 1 to 20 carbon atoms,halogen, hydroxy, hydrogen, and groups of the following general formula:

wherein R² has the definition indicated above and n=1 to 3, m=1 to1,000, p=1 to 5, q=1 to 3, and x=1 to 8; and

b) 30 to 95, preferably 40 to 60, parts by weight of one or more of thecommon reinforcing semiactive, active, and/or highly active carbonblacks.

Oligo/poly[4-(2-trialkoxysilylethyl)cyclohexane-1,2-diyl]bisoligosulfidesof the following general formula:

wherein R², m, and x have the definitions indicated above, arepreferably used as sulfur-containing organoorganooxysilanes.

Moreover, a number of other oligomeric and polymeric, sulfur-containingorganoorganooxysilanes can, of course, be used.

Examples of such compounds are the following:

oligo/poly[5-triethoxysilyl)bicyclo[2.2.1]heptane-2,3-diyl]bisoligosulfides of the following general formula:

oligo/poly[8,9-bis(triethoxysilyl)-endo-tricyclo[5.2.1.0^(2.6)]decane-3,4-diyl]bisoligosulfides of the following generalformula:

oligo/poly[trialkoxysilyl)alkane-1,2-diyl]bisoligosulfides of thefollowing general formula:

oligo/poly[1-(trimethoxyethoxysilyl)ethane-1,2-diyl]bisoligosulfides ofthe general formula:

oligo/poly[3,3,5,5-tetraethoxy-4-oxa-3,5-disilaheptane-1,2,6,7-tetrayl]tetrakisoligosulfidesof the following general formula:

The values for x are 1 to 8, those for m=1 to 200.

The reinforcement additives in accordance with the invention can containup to 20 parts by weight of one or more organoorganooxysilanes of thefollowing general formula:

R⁴—Si(OR²)_(n)R³ _((3−n))  (V),

wherein R², R³, and n have the aforementioned definitions and R⁴represents unsaturated, branched, and/or unbranched, substituted and/orunsubstituted hydrocarbons with 2 to 20 carbon atoms and with at leastone double bond of an olefinic or aromatic character.

Compounds of general formula (IV) are, for example, the following:

2-[(3-cyclohexen-1-yl)ethyl]trialkoxysilane,

2-(phenylethyl)trialkoxysilane, and/or,

alkenyltrialkoxysilanes with up to 20 carbon atoms in the alkenylgroup,wherein alkoxy=OR² with R² having the definition indicated above.

Furthermore, the sulfur-containing organoorganooxysilanes of generalformula (I) can contain additives that are common in rubber, such as,for example, accelerators, crosslinking agents, and or free sulfur. Itis, however, also possible to admix these additives separately.

In addition to the usual reinforcing furnace carbon blacks, channelblack, thermal black, lampblack, acetylene black, and/or arcblack carbonblacks, as well as active carbon, are also used in the silane-carbonblack mixtures in accordance with the invention.

For use in silicatically filled rubber mixtures, the silane-carbon blackadditives in accordance with the invention preferably consist of 40 to60 parts by weight of the described organoorganooxysilanes and 40 to 60parts by weight carbon blacks, common in rubber.

The object of the invention is also a method for the preparation of thereinforcement additives, described above, and in accordance with theinvention, consisting of sulfur-containing oligomeric and/or polymericsilanes and carbon blacks, which is characterized by the fact that

a) the oligomeric and/or polymeric, sulfur-containingorganoorganooxysilanes of general formula (I);

b) the reinforcing semiactive, active, and/or highly active carbonblacks, and

c) perhaps other additives are mixed in a common continuously ordiscontinuously operating mixing apparatus at room temperature, untilthe organoorganooxysilane is adsorbed on the carbon black and anonadhesive granulated material is obtained.

Advantageously, the unsaturated hydrocarbon-containingorganoorganosilanes of general formula (IV), just like the additives orfree sulfur common in rubber, are added, as needed, to thesulfur-containing organoorganooxysilanes of general formula (I) beforethe mixing.

Someone skilled in the art is aware that oligomeric and polymericsilanes or siloxanes with carbon blacks rather produce adhesive ornongranulatable products or products that can be granulated only withdifficulty. It was all the more surprising that when metering theoligomeric and/or polymeric, sulfur-containing organoorganooxysilanes tothe carbon black present, it was possible to obtain a very readilyprocessable, granulatable silane-carbon black batch after a shortadsorption time.

Particularly advantageous characteristics of the silane-carbon blackreinforcement additives in accordance with the invention are attainedwhen using the compounds of general formulas (IV) and (VI) to (IX).

The silane-carbon black reinforcement additives in accordance with theinvention are obtained as solid, flowable, odorless, dust-free,storage-stable silane-carbon black preparations, present in a narrowparticle size distribution, in which the weight ratios are freelyselectable in the ranges 5 to 70 parts by weight silane and 30 to 95parts by weight carbon black.

Another object of the invention is the use of the reinforcementadditives in accordance with the invention in vulcanizable rubbermixtures and compositions, plastic mixtures, and carbon blackdispersions—that is, which can be crosslinked with sulfur or peroxides.In particular, silicatically filled rubber mixtures and compositions arepreferred thereby.

The reinforcement additives in accordance with the invention are addedto the silicatically filled rubber mixtures in quantities of 1 to 100parts, preferably in a quantity of 2 to 50 parts, based on 100 partsrubber.

With the additives in accordance with the invention, it was possible toattain considerable advantages, in comparison to vulcanized materials inwhich the oligomeric and/or polymeric silanes were used without priormixing with carbon black, or in comparison to vulcanized materials thatcontain traditional silanes, which are known for this applicationpurposes, with or without carbon black. Thus, silicatically filledrubber mixtures that contained the reinforcement additive in accordancewith the invention exhibit clearly improved physical-mechanical anddynamic coefficients, in addition to a high processing reliability.Unexpectedly, the tear resistance rather had a tendency to increase, andelongation at break and mixing viscosity did not reach any criticalvalues.

Among the rubber types suitable for use with reinforcement additives inaccordance with the invention are both the natural or synthetic rubbersand their mixtures, which can be crosslinked with sulfur and withperoxides. One can mention as examples here: styrene-butadiene rubber,natural rubber, EPDM rubbers, nitrile rubber, and polychloroprene.

As light reinforcement fillers, it is possible to use all lightsilicatic fillers, which are made of silicates and contain silicates andwhich are compatible with respect to rubber and can be worked intorubber mixtures, in particular natural, pyrogenic or precipitatedsilicas and synthetic or naturally occurring silicates.

Moreover, the rubber mixtures mixed with the reinforcement in accordancewith the invention contain other known additives common in rubber, suchas:

reinforcement carbon blacks (mentioned individually above),

inactive fillers, such as calcium carbonates, chalks, talcs, or metaloxides,

crosslinking agents and accelerator systems,

vulcanization retarders,

promoters, such as zinc oxide or stearic acid,

plasticizers, in particular aromatic, paraffinic, naphthenic orsynthetic mineral oils,

ageing, light-protecting, ozone-protecting, fatigue, coloration. andprocessing auxiliaries,

sulfur, in a quantity of 0.1 to 8 parts by weight per 100 parts byweight rubber.

The mixtures are prepared in the manner common in rubber in a closedmixer and/or on a rolling mill.

The reinforcement additives in accordance with the invention are usedboth in mixtures for the production of tires in the form of bearingsurface, sidewall, adhesion, belt, carcass, and beaded ring mixtures andin mixtures for technical articles, for example, for hoses, sealings,conveyance belts, spring and damping elements or rubber-coated fabrics.

Previously known reinforcement additives permitted the firm binding ofonly a fraction between 0.5 and 5.5 wt % of the used silane to or on thecarbon black. The remaining fraction could be dissolved out from themixture by extraction, for example, with ether. Therefore, it wascompletely surprising that although the preparation was carried out at25° C., 50 to 60 wt % of the silane fraction were bound to the carbonblack and only 40 to 50 wt % could be extracted from the reinforcementadditives in accordance with the invention.

The reinforcement additives in accordance with the invention aresuperior to the pure silanes and commercial silane-carbon blackpreparations in their effectiveness, above all in silicatically filledrubber mixtures. This technical progress is attained surprisingly by thecombination of oligomeric and polymeric sulfur-containingorganoorganooxysilanes with reinforcer carbon blacks common in rubber.

Other advantages are to be found in the simple and economicalpreparation of the additives in accordance with the invention and in arapid dispersion and processing capacity in the rubber mixtures. As aresult of the improved heat build-up and the excellent dynamic andphysical-mechanical characteristics in silica-filled tire vulcanizedmaterials, an application of the mixtures in accordance with theinvention in so-called eco-tires [sic] is possible.

The reinforcement additives in accordance with the invention exhibit ahigh effectiveness, particularly in vulcanizable, silicatically filledrubbers. Thus, when using the preparations in accordance with theinvention in silica-filled rubbers, with a high processing reliability,excellent physical-mechanical coefficients and dynamic characteristicsare implied. The clear improvement of stress values and heat build-uptakes place, for example, without an impairment of the tear propagationresistances or a reaching of critical values with vulcanization timesand elongation values. Such a combination of rubber characteristics isnot attainable with the previously known silane-carbon black systems.

EXECUTION EXAMPLES Preparation of the Mixtures in Accordance with theInvention Examples 1-18

In a generally common 10-L shear blade mixer FM 10 from the ThyssenHenschel Company with horn-like fluidizing blades as a mixing tool,cooling jacket, and temperature measurement, 1 kg of the carbon black orcarbon black mixture to be used were present and the sulfur-containingorganoorganooxysilanes to be used were added via an inflow in the lid ofthe mixer at room temperature within 10 min with nitrogen misting withrotational speeds of 100 to 200 min⁻¹. This was followed by anadsorption time of 8 to 10 min with an rpm<50 min⁻¹. For the adjustmentof a narrow particle size distribution in the formed granulatedmaterial, shear energy was introduced in short intervals (3 to 5×20 sec)with a rotational speed of 500 min⁻¹. During the entire process, theheat formed by the adsorption of the sulfur-containingorganoorganooxysilane on the carbon black and by the introduced shearenergy was removed via the cooling jacket. After a total residence timeof 20 to 30 min, the mixing apparatus was emptied, and the silane-carbonblack reinforcement additives were obtained as flowable, odorless,adhesive-free and nondusting granulated materials with a narrow particlesize distribution.

The sulfur-containing oligomeric and polymeric organosilanes used werethe following:

A) oligo/poly[4-(2-triethoxysilylethyl)cyclohexane-1,2-diyl]bisoligosulfides of thefollowing general formula:

x=1 to 8

m=1 to 200

S content: 24 wt %

B) oligo/poly[8,9-bis(triethoxysilyl)-endo-tricyclo[5.2.1.0^(2.6)]decane-3,4-diyl]bisoligosulfides of the following generalformula:

x=1 to 8

m=1 to 200

S contnet: 27.3 wt %

C)oligo/poly[5-(triethoxysilyl)bicyclo[2.2.1]heptane-2,3-diyl]bisoligosulfidesof the following general formula:

D) oligo/poly[1-(trimethoxyethoxysilyl)ethane-1,2-diyl]bisoligosulfidesof the following general formula:

x=1 to 8

m=1 to 200

S content: 25.5 wt %

E)oligo/poly[3,3,5,5-(tetraethoxy-4-oxa-3,5-disilaheptane-1,2,6,7-tetrayl]tetrakisoligosulfidesof the following general formula:

x=1 to 8

m=1 to 20

S contnet: 23.9% wt %

The carbon blacks used were the following:

Type Manufacturer F Statex N 330 Columbian Carbon Deutschland GmbH GCorax N 110 Degussa AG H Corax N 220 Degussa AG I Corax N 330 Degussa AGK Elftex 285 (N 550) Cabot Europa Ltd. L Elftex 465 (N 330) Cabot EuropaLtd.

The additives used for the sulfur-containing organoorganooxysilane werethe following:

M Sulfur (dissolved) N 2-[(3-Cyclohexen-1-yl)ethyl]triethoxysilane O2-(Phenylethyl)triethoxysilane P Tetramethylthiuramdisulfide

Starting materials, parameters for the mixing process, and data for theobtained results for Execution Examples 1 to 18 are given in Table I.

TABLE I Mixing Starting Material Conditions Preparations Silane Periodof Bulk Particle size Ex. Additive Additive Carbon Temp Preheat- Densitydistribution No. Silane Wt. % (Kg) Black ° C. ing (min.) g/cm³ wt. %-mm1 A — — 1 F 1 25 20 0.37 90 0.2-1.0  9 1.0-2.0 2 A — — 1.4 F 0.6 25 200.41 90 0.5-1.4  9 1.4-2.0 3 A — — 1 K 1 25 25 0.20 90 1.5-2.5  92.5-3.5 4 A — — 1 L 1 25 22 0.16 90 0.5-1.4  9 1.4-2.0 5 A — — 1 F 0.525 22 0.31 90 0.4-1.3 L 0.5  8 1.3-2.0 6 A — — 1 F 0.5 25 22 0.33 900.4-1.4 K 0.5  8 1.4-2.0 7 A — — 1 I 1 25 25 0.54 90 0.5-1.5  8 1.5-2.08 A — — 1 H 1  25- 25 0.58 90 1.0-2.0 30  7 2.0-2.5 9 A — — 0.7 I 1.3 2522 0.47 90 0.5-1.4  9 1.5-2.0 10  A — — 0.1 G 1.9 25 20 0.35 90 0.1-0.8 7 0.8-2.0 11  A M  2 1 F 1 25 20 0.37 90 0.2-1.0  8 1.0-2.0 12  A N  51 F 1 25 20 0.37 90 0.2-1.0  8 1.0.2.0 13  A O 10 1 L 1 25 22 0.17 900.5-1.4  8 1.4-2.0 14  A P 10 1 F 1 25 20 0.36 90 0.2-1.0  7 1.0-2.0 15 B — — 1 F 1 25 20 0.37 90 0.5-1.5  8 1.5-2.2 16  C — — 1 F 1 25 20 0.3790 0.1-1.0  8 1.0-2.0 17  D — — 1 F 1 25 22 0.37 90 0.2-1.1  8 1.1-2.018  E — — 1 F 1 25 22 0.37 90 0.3-1.2  9 1.2-2.1

The prepared silane-carbon black preparations were tested for theireffectiveness as reinforcement additives in silica-filledstyrene-butadiene rubber mixtures in the indicated composition (data onquantities in parts by weight):

in each case, in comparison with an 0 mixture, without an addition ofsilane-carbon black mixtures;

in comparison with comparative mixtures, which contained the silane usedin pure form;

in comparison with rubber mixtures, whose commercially available carbonblack-silane preparations were added.

The vulcanized materials were prepared in a two-stage procedure, whichis common in the rubber industry. The basic mixture was prepared in aclosed mixer and mixed completely on a rolling mill with the addition ofcrosslinking chemicals. Test specimens were produced by vulcanization inthe usual manner from these rubber mixtures.

The raw materials in the vulcanized material preparation were thefollowing:

Buna Hüls EM 1502 SBR Buna Hüls EM 1712 SBR, oil-filled (37.5 partsaromatic mineral oil) Ultrasi VN3 Precipitated silica Circosol 4240Paraffinic mineral oil Q8 Purcell 900P Paraffinic mineral oil Lipoxol4000 Polyethylene glycol Vulkanox HS (TMQ) 2,2,4-Trimethyl-1,2-dihydroquinoline Vulkanox 4010 NA (IPPD) N-Isopropyl-N′-phenyl-p-phenylenediamine Vulkanox 4020 (6 PPD) N-1,3-Dimethylbutyl-N′-phenyl-p-phenylenediamine Vulkacit CZ (CBS) Benzothiazyl-2-cyclohexylsulfeneamide Vulkacit D (DPG) Diphenylguanidine Vulkacit NZ(TBBS) Benzothiazyl-2-tert- butylsulfeneamide

The test standards for the application-technical investigation were thefollowing:

Mooney viscosity ML (1 + 4): DIN 53523 Parts 1-3 t₁₀, t₉₀: Din 53523Part 4 Tensile strength, DIN 53504 elongation at break, stress value(modulus), 100%, 200%, 300% (rod and ring): Permanent extension: DIN53518 Hardness (Shore A): DIN 53505 Tear propagation resistance: DIN53507 Rebound resilience: DIN 53512 Compression Set: DIN 53517 Wear: DIN53516 Goodrich Flexometer: DIN 53533 Part 3 Ball crushing according toMartens

Recipe I

SBR (Styrene-butadiene rubber) Comparison of 4 rubber mixtures withdifferent quantities of the reinforcement additives according to Example1 with the corresponding 0 mixture without reinforcement additive.

TABLE II Mixture No. 001 002 003 004 005 Buna Hüls EM 1502 100 100 100100 100 Ultrasil VN3 60 60 60 60 60 Circosol 4240 7.5 7.5 7.5 7.5 7.5Zinc Oxide 5 5 5 5 5 Lipoxol 4000 2 2 2 2 2 Vulkanox HS 1 1 1 1 1Stearic Acid 1.5 1.5 1.5 1.5 1.5 Sulfur 1.6 1.6 1.6 1.6 1.6 Vulkacit NZ1.6 1.6 1.6 1.6 1.6 Vulkacit D 0.8 0.8 0.8 0.8 0.8 Carbon Black F — — —— — Additive according to — 3.0 6.0 9.0 12.0 Example 1 Total 181 184 187190 193

Vulcanization Characteristics of the Mixtures According to Recipe I

TABLE III Mixture No. 001 002 003 004 005 Mooney-Viscosity ML (1 +4)100° C. 81 77 81 82 82 Curemeter 160° C. t₁₀ (min) 12.6 9.6 8.2 7.16.3 t₉₀ (min) 19.1 16.6 14.8 13.5 12.8 t₉₀-t₁₀ (min) 5.5 7.0 6.6 6.4 6.5Vulcanization 30 min 67 67 73 74 76 160° C. Hardness (Shore A) TensileStrength (MPa) 9.0 14.8 22.6 26.5 25.8 Modulus 100% (MPa) 1.3 1.8 2.5*3.3 3.5 Modulus 200% (MPa) 1.9 3.4 5.5 7.7 8.9 Modulus 300% (MPa) 2.75.9 10.3 14.0 15.7 Elongation at Break (%) 672 612 488 471 417 TearPropagation Resistance (N/mm) 16 20 18 17 16 Rebound resilience (%) 4343 44 44 43 Compression Set 72 h 70° C. (%) 29 30 24 22 22 Wear (mm³)278 162 145 127 119 Goodrich-Flexometer Method 1 53 35 39 40 41 ΔT after25 min (° C.) Flow after 25 min (%) −10.5 −3.0 −2.4 −2.0 −1.5 Permanentset (%) 12.7 5.2 6.0 4.8 4.1

By using the reinforcement additives in accordance with the invention,the starting vulcanization times were shortened with the increasingfraction of the additives, wherein they did not drop below criticalorders of magnitude. Unexpectedly, the Mooney viscosity remained almostconstant and the vulcanization time rose slightly.

The physical-mechanical and dynamic coefficients of the vulcanizedmaterials obtained exhibited improvements by several orders of magnitudein the presence of the preparations in accordance with the invention. Itis of particular interest that despite a clearly positive development ofthe tensile strength, moduli, hardness, compression set, wear, andFlexometer values, the tear propagation resisance was also positive andthe rebound resilience remained practically uninfluenced.

Recipe II

SBR tire mixture

Comparison of 6 typical rubber mixtures of passenger vehicle tires withdifferent compositions with the reinforcement additives in accordancewith the invention (Examples 1, 4, and 7) with the corresponding 0mixture without a reinforcement additive. The carbon black types and thequantities of the additives in accordance with the invention, based onrubber and filler fractions, were thereby varied.

TABLE IV Mixture No. 006 007 008 009 010 011 012 Buna Hüls EM 1712 137.5137.5 137.5 137.5 137.5 137.5 137.5 Ultrasil VN3 75 75 75 75 75 75 75 Q8Purcell 900 P — 2.5 5 2.5 5 2.5 5 Zinc Oxide 5 5 5 5 5 5 5 Stearic Acid1.5 1.5 1.5 1.5 1.5 1.5 1.5 Koresin-Resin 2 2 2 2 2 2 2 Vulkanox 4010 NA1 1 1 1 1 1 1 Vulkanox 4020 1 1 1 1 1 1 1 Sulfur 1.6 1.6 1.6 1.6 1.6 1.61.6 Vulkacit NZ 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Vulkacit D 1.2 1.2 1.2 1.21.2 1.2 1.2 Carbon Black F — — — — — — — Additive according to theinvention Preparation Example 1 — 6 12 — — — — Preparation Example 4 — —— 6 12 — — Preparation Example 7 — — — — — 6 12 Total 227.4 235.9 244.4235.9 244.4 235.9 244.4

Vulcanization Characteristics of the Mixtures According to Recipe II

TABLE V Mixture No. 006 007 008 009 010 011 012 Mooney-Viscosity ML (1 +4) 87 73 64 75 71 72 68 100° C. Cure meter 160° C. τ₁₀ (min)  τ₉₀ 1.28.1 7.3 8.1 6.6 8.6 7.0 (min)  τ₉₀-τ₁₀ 44.2 26.0 19.1 23.9 17.9 24.0(min) 43 17.9 11.8 15.8 11.3 15.4 18.2 11.2 Vulkanisation 30 min 160° C.48 56 60 55 61 54 61 Hardness (Shore A) (MPa) 5.3 13.2 15.7 13.7 17.012.9 Tensile Strength 17.0 Modulus 100% (MPa) 0.6 1.0 1.4 1.0 1.65 1.01.6 Modulus 200% (MPa) 0.8 8.0 3.3 2.1 3.8 2.0 3.8 Modulus 300% (MPa)1.2 3.6 6.03 3.80 7.0 3.5 6.8 Elongation of Break (%) 1054 756 633 747611 747 626 Tear Propagation Resistance (N/mm) 19 25 23 24 20 27 20Rebound Resilience (%) 39 39 38 40 39 40 39 Wear (mm³) (*) (*) 275 226281 173 264 157 Goodrich-Flexometer, (*1) 41 31 41 29 41 29 Method 1 ΔTafter 25 min (° C.) Flow after 25 min (%) (*1) −5.9 −1.1 −6.0 −0.8 −5.5−1.0 Permanent Set (%) (*1) 8.7 3.1 8.7 2.4 8.7 2.4 Ball Crushing afterMartens 150 N (° C.) 120 142 111 138 103 139 105 200 N (° C.) 5 13 157203 145 14.8 147 (*2) (*2) (*2) 250 N (° C.) — — 186 — 178 — 181 300 N(° C.) — — 3 — 3 — 3 (*2) (*2) (*2) (*) Not measurable - sample too soft(*1) Not measurable - definition too high (*2) Destruction of sample

The reinforcement additives in accordance with the invention broughtabout a clear improvement in almost all the physical-mechanical anddynamic parameters in the tire mixtures. In spite of the high reinforcereffect by the preparations in accordance with the invention, thestarting and completing vulcanization times and the elongation at breakdid not fall below critical orders of magnitude.

Surprisingly, the tear propagation resistance also did not fall belowthe value of the zero mixture, as was otherwise common with, with ahigher metering of the reinforcement preparation.

On the basis of the clearly improved heat build-up (ball crushing andthe reduced surface tension of the obtained rubber samples, caused bythe content of silica, recipes of this type are also suitable for thedevelopment of eco-tires.

Recipe III

SBR test mixture

Comparison of rubber mixtures without a silane fraction, with freesilane, and with the reinforcement additive in accordance with theinvention.

TABLE VI Mixture No. 013 014 015 Buna Hüls EM 1502 100 100 100 ZincOxide 5 5 5 Stearic Acid 2 2 2 Ultrasil VN3 50 50 50 Diethylene glycol 33 3 Vulkacit CZ 1.2 1.2 1.2 Vulkacit D 1.0 1.0 1.0 Sulfur 2.0 2.0 2.0Carbon Black F — — — Oligo-[4-(2-triethoxysilylethyl)- — 2 —cyclohexane-1,2- diyl]bisoligosulfid (S-content: 24%) Inventive AdditiveAccording to Ex. 1 — — 4 Total 164.2 166.2 168.2

Vulcanization Characteristics of the Mixtures According to Recipe III

TABLE VII Mixture No. 013 014 015 Mooney-Viscosity ML (1 + 4) 100° C. 8175 79 Curemeter 150° C. t₁₀ (min) 19.3 14.8 15.2 t₉₀ (min) 27.0 23.424.6 t₉₀ − t₁₀ (min) 7.7 8.6 9.4 Vulkanization 35 min 150 ° C. 65 71 73Hardness (Shore A) Tensile Strength 12.4 13.7 13.9 Modulus 300% (MPa)3.7 7.2 9.8 Elongation at break (%) 611 465 413 Elongation at set (%) 3017 15 Rebound Resilience (%) 43 44 45 Wear (mm³) 156 92 82Goodrich-Flexometer Method 1 38 26 24 Δ after 25 min (° C.) Flow after25 min (%) −1.04 0.06 0.334 Permanent set (%) −4.2 0.2 1.3

In a comparison of the coefficients of the vulcanizate, using thereinforcement additives in accordance with the invention, with thevulcanized material, which contained the corresponding pure silane, aclear superiority of the silane-carbon black preparation in accordancewith the invention is exhibited. All vulcanization characteristicstested, with the natural exception of the elongation at break, wereclearly improved when using the silane-carbon black mixture of theinvention in comparison to the pure silane.

Recipe IV

SBR

Comparison of rubber mixtures without silane fraction with thesilane-carbon black preparation in accordance with the inventionaccording to Example 7 and a silane-carbon black preparation, prepared(according to West German Patent No. 2,747,277) from the carbon blackCorax N 330 and the commercially available, monomeric sulfur-containingsilane bis[3-triethoxysilylpropyl]tetrasulfide (Si 69 from the DegussaCompany, Frankfurt) in the mass ratio 50:50.

TABLE VIII Mixture No. 016a 017 018 Buna Hüls EM 1502 100 100 100Ultrasil VN3 60 60 60 Circosol 4240 7.5 7.5 7.5 Zinc Oxide 5 5 5 Lipoxol4000 2 2 2 Vulkanox HS 1 1 1 Stearic Acid 1.5 1.5 1.5 Sulfur 1.6 1.6 1.6Vulkacit NZ 1.6 1.6 1.6 Vulkacit D 0.8 0.8 0.8 Carbon black-Silanepreparation — 9.0 — Corax N 330 and Bis-(3-triethoxysilylpropyl]tetrasulfid in a 50:50 weight ratio InventiveCarbon black additive — — 9.0 according to Example 7 Total 181 190 190

Vulcanization Characteristics of the Mixtures According to Recipe IV

TABLE IX Mixture No. 016 017 018 Mooney-Viscosity ML (1 + 4) 81 80 82100° C. Curemeter 160° C. t₁₀ (min) 12.9 7.2 7.3 t₉₀ (mim) 19.1 13.814.0 t₉₀ − t₁₀ (min) 5.2 6.6 6.7 Vulkanisation 30 min 160° C. 67 74 75Hardness (Shore A) Tensile strength (MPa) 9.0 23.9 26.6 Modulus 300%(MPa) 2.5 (14.0)* 14.2 Elongation at break (%) 675 319 368 Tearpropogation resistance (N/mm) 16 14 17 Compression set 72 h 100° C. (%)66 53 49 Wear (mm³) 280 136 127 Goodrich-Flexometer, Method 1 53 36 37ΔT after 25 min (° C.) Flow after 25 min (%) −10.5 −1.1 −1.8 Permanentset (%) 12.8 3.6 3.5 *Defective, since elongation at break was 319%

A comparison of mixtures 017 and 018 shows that considerableimprovements, in comparison with the state of the art, were attainedwith the reinforcement additives in accordance with the invention.Whereas the Flexometer exhibited comparable values, the curemeter dataindicated a higher processing reliability when using the preparations inaccordance with the invention. On the basis of physical-mechanicalcoefficients, such as wear and compression set, but above all, tearpropagation resistance, elongation at break, and tensile strength, theadvantages of the new preparations are clearly visible.

Reinforcement additives

What is claimed is:
 1. A reinforcement additive, comprising a mixtureof: a) 5 to 70 parts by weight of one or more oligomeric and/orpolymeric silanes of the formula:

wherein R¹ is a saturated or unsaturated, branched or unbranched,substituted or unsubstituted at least trivalent hydrocarbon group having2-20 carbon atoms, containing at least two carbon-sulfur bonds, R² andR³ are, independently, saturated or unsaturated, branched or unbranched,substituted or unsubstituted hydrocarbon groups having 1-20 carbonatoms, halogen, hydroxy, hydrogen or a group of the formula (II) or(III):

wherein R² is as defined above and n=1-3, m=1-1,000, p=1-15, q=1-3 andx=1-8; and b) 30-95 parts by weight of semiactive, active or highlyactive carbon black.
 2. The additive of claim 1, wherein said silane isanoligo/poly(4-(2-trialkoxysilylethyl)cyclohexane-1,2-diyl)bisoligosulfideof the formula:

wherein R², m and x are as defined above.
 3. The additive of claim 1,further comprising up to 20 parts by weight of an organo-oxysilane ofthe formula: R⁴-Si(OR²)_(n)R³ _((3−n))  (V) wherein R², R³ and n are asdefined above and R⁴ is an unsaturated, branched or unbranched,substituted or unsubstituted hydrocarbon having 2-20 carbon atoms andcontaining at least one carbon—carbon olefinic or aromatic double bond.4. The additive of claim 3, wherein said organooxysilane is a2-((3-cyclohexene-1-yl)ethyl)trialkoxysilane or2-(phenylethyl)trialkoxysilane.
 5. The additive of claim 1, furthercomprising free sulfur.
 6. The additive of claim 1, comprising 40-60parts by weight of component (a) and 60−40 parts by weight of component(b).
 7. A rubber or plastic mixture, comprising rubber or plastic andthe additive of claim
 1. 8. The mixture of claim 7, further comprising asilicate filler.
 9. The mixture of claim 7, further comprisingprecipitated silica.
 10. A method of preparing the additive of claim 1,comprising the step of: mixing component (a) and component (b) untilsaid silane is adsorbed onto said carbon black, producing a nonadhesivegranulated additive.